Shredded Pine Bark vs. Pine Needles

This is probably a very dumb question, but:  Since the texture of shredded bark is different from pine needles, I'm wondering do they both impart the same acidity to soil? 

My neighbor had a ton of pine trees cut down.  The stumps were ground down.  The result is lots of free shredded pine bark for my mulching needs.

I also have lots of pine straw in my own yard, but I've read lots of folks really like shredded bark.

So...  Do both mulches have the same effect on the soil?  And, if acidity will be a problem, is there a good and safe way to balance the pH (e.g. dolomite or lime)? 

Thanks all~

Wind

Here is a little research I just did to help answer your question.  There is much more out there - google pine bark acidity.

http://wood.uwex.edu/2010/11/18/pine-needles-cause/
Believe it or not, this is fiction, a myth. Pine needles do not make the soil more acidic. This bit of garden lore is so common that almost everyone believes it, including many professionals. It is true that the soil most pine trees grow in is acidic, sometimes only slightly, but acidic nonetheless. Was this acidity caused by the pines? Most evergreen species prefer soils that are on the acid side, as do oak, maple, and many other plants. But they did not begin growing in an area and then change the soil to suit their requirements. It would be great if plant could actually do that!
Now, I would like to do a little bit of clarification of this statement because I may have ruffled a few feathers. Many materials are acidic before they are broken down. Pine needles and oak leaves both have pH’s ranging between 3.2 and 3.8 when they fall from the tree. If those materials are incorporated into the soil before decomposing, they may have a small effect on the soil pH. If those raw materials are used on the soil surface as mulch, they will have very little effect on plant growth because the roots are not growing in this material. As the leaves and needles break down, they are neutralized by the microbes that are doing the decomposing work. Most compost has a pH of 6.8-7.0, which is very neutral. Dr. Maynard from UCONN Ag Research Station has done several studies showing the effects of mulch on soil pH

http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=223401
In both experiments, the mulches were mixed into the topsoil to accelerate rotting. Pine straw did not increase topsoil acidity in the field experiment, while nitrogen fertilizer increased acidity. Pine straw and pine bark mulch increased topsoil acidity in the container experiment.

http://www.uaex.edu/Other_Areas/publications/PDF/FSA-6097.pdf

Sorry, I do not know anything about using lime etc to change ph.

Hi Yolos,

Thanks very much for your informative post.  I love that the USDA Research Project was brief and easy to understand. 

The University of Arkansas paper made some interesting comments.  One being that pine bark contains fewer leachable organic acids than hardwood bark.  Also, it is good to know that hardwood bark typically contains toxic compounds and should only be used after composting.

I feel better about using the shredded pine bark.  I think, to be on the safe side, I may have the soil tested from time to time (depending on how the plants look).

Thank you Yolos.  You are always a good resource!


Wind